Telescoping sleeve and sleeve assembly

Abstract

The application discloses a telescopic casing, relates to the technical field of drilling equipment, and comprises an outer pipe assembly, an inner pipe assembly and a locking and pushing assembly. The top end of the outer pipe assembly is used for being connected with a casing string. The inner pipe assembly is coaxially installed in the outer pipe assembly and can move along the axial direction of the outer pipe assembly. The bottom end of the inner pipe assembly extends out of the outer pipe assembly and is used for being connected with a butt joint tool. The bottom end of the locking and pushing assembly can be locked with the top end of the inner pipe assembly through locking structure. The top end of the locking and pushing assembly is used for being connected with a drill pipe column. The inner pipe assembly and the inner wall of the outer pipe assembly are locked through locking pieces. When the drill pipe column pushes the inner pipe assembly downwards, the locking pieces can be unlocked, so that the inner pipe assembly moves forwards relative to the outer pipe assembly. The application further discloses a casing assembly which comprises a butt joint tool, a casing and the telescopic casing. The telescopic casing can realize controllable extension at the well bottom, so that the distance between the butt joint tool and a target body can be actively adjusted, and different drilling lengths can be adapted.

Description

Technical Field

[0001] This invention relates to the field of drilling equipment technology, and in particular to a telescopic casing and casing assembly. Background Technology

[0002] The purpose of directional drilling is to precisely drill into a predetermined formation or target point according to the designed trajectory. During the drilling process, depending on the well design, multiple stages of casing strings need to be run. In oil and gas drilling, a wellhead is generally set up to install blowout preventers and mount the casing.

[0003] In some applications, the casing string is not connected to the drilling vessel or platform but is lowered into the wellbore and hooked to the wellhead via a casing hanger. Therefore, the length of the casing string needs to be matched to the drilling depth. For conventional casing cementing, the length of the casing string does not require precise matching with the well depth. However, in applications requiring target alignment, a mismatch in casing string length can lead to two problems: either the front end of the casing string cannot contact the target after being hooked, or the casing string is not properly hooked after docking with the target. Given these two possibilities, after the casing string is hooked, the distance between the docking tool and the target needs to be adjusted to accommodate the drilling length.

[0004] Currently, telescopic sleeves are typically installed on the casing string to adjust the casing length. Existing telescopic sleeves generally consist of two layers, with the inner sleeve sliding inside the outer sleeve to achieve telescopic movement (e.g., a telescopic sleeve for marine drilling, CN212837619U; a telescopic sleeve for drilling in tidal areas, CN215761533U). However, the aforementioned telescopic sleeves are mainly used to compensate for the casing's up-and-down movement caused by the drilling vessel or platform following the waves. The telescopic sleeve is installed inside the casing string to compensate for changes in casing length caused by the movement of the drilling vessel or platform. Its main function is passive length compensation. The telescopic sleeve itself does not have a locking structure, so it is impossible to control when it extends or retracts, and it is impossible to actively adjust the distance between the docking tool and the target.

[0005] Therefore, there is an urgent need to provide a new telescopic sleeve to solve the above-mentioned problems existing in the prior art. Summary of the Invention

[0006] The purpose of this invention is to provide a telescopic casing and casing assembly to solve the problems existing in the prior art. It can achieve controllable extension to the bottom of the well, so as to actively adjust the distance between the docking tool and the target and adapt to different drilling lengths.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] This invention provides a telescopic sleeve, comprising an outer tube assembly, an inner tube assembly, and a locking and pushing assembly. The top end of the outer tube assembly is used for connection with a sleeve string. The inner tube assembly is coaxially installed inside the outer tube assembly and is movable along the axial direction of the outer tube assembly. The bottom end of the inner tube assembly extends out of the outer tube assembly and is used for connection with a docking tool. The bottom end of the locking and pushing assembly can be locked to the top end of the inner tube assembly through a locking structure. The top end of the locking and pushing assembly is used for connection with a drill string.

[0009] The inner tube assembly and the inner wall of the outer tube assembly are locked together by a locking member. When the drill string pushes the inner tube assembly downward, the locking member can be unlocked, so that the inner tube assembly can move forward relative to the outer tube assembly.

[0010] Preferably, the outer tube assembly includes a sealing joint, an outer tube, and a sleeve joint. The sleeve joint is connected to the top end of the outer tube for connection with the sleeve in series. The sealing joint is connected to the bottom end of the outer tube and is locked to the inner tube assembly by the locking member.

[0011] Preferably, both the sealing joint and the sleeve joint are installed on the outer tube by set screws, and sealing rings are provided on both sides of the set screws.

[0012] Preferably, the telescopic sleeve further includes an intermediate tube, which is coaxially disposed within the outer tube assembly. One end of the intermediate tube is connected to the sleeve joint via a limiting structure, and the other end of the intermediate tube is connected to the sealing joint via a limiting structure. The limiting structure is used to restrict the relative rotation between the intermediate tube and the outer tube assembly. The inner tube assembly is slidably disposed within the intermediate tube so that the inner tube assembly can move axially along the outer tube assembly.

[0013] Preferably, the intermediate tube has a guide groove along the axial direction, and the inner tube assembly has a guide block, which is slidably disposed in the guide groove.

[0014] Preferably, the inner tube assembly includes an inner tube and an inner tube connector. The bottom end of the inner tube is provided with a male buckle for connecting with the docking tool, and the inner tube is locked to the sealing joint by the locking member. The top end of the inner tube is provided with a female buckle for connecting with the inner tube connector, and the top end of the inner tube connector can be locked to the locking push assembly by the locking structure.

[0015] Preferably, the locking element is a locking pin, which can disengage when the drill rod pushes the inner tube assembly downward, thereby unlocking the device;

[0016] The outer tube assembly has multiple pin holes evenly arranged circumferentially at its front end, and the pin holes penetrate the outer tube assembly radially. The inner tube assembly has multiple blind holes correspondingly arranged on it. The locking pin passes through the pin holes and extends into the corresponding blind holes to lock the outer tube assembly and the inner tube assembly.

[0017] Preferably, a sealing ring and a dustproof ring are provided between the inner tube assembly and the front inner wall of the outer tube assembly.

[0018] Preferably, the locking structure includes a locking groove structure and a locking pusher. When the locking pusher is screwed into the locking groove structure in a first direction, the inner tube assembly and the locking pusher assembly are locked. When the locking pusher is rotated in a second direction, it can be screwed out of the locking groove structure, thereby unlocking the inner tube assembly and the locking pusher assembly.

[0019] The locking groove structure is provided on the inner tube assembly, including two arc grooves arranged in opposite directions along the circumference. The locking pusher is provided on the locking pusher assembly and extends radially along the locking pusher assembly. A sealing element is also provided on the inner wall of the inner tube assembly near the locking pusher assembly to achieve a seal with the locking pusher assembly.

[0020] The present invention also provides a sleeve assembly, including the docking tool, the sleeve string, and the telescopic sleeve as described above.

[0021] The present invention achieves the following technical effects compared to the prior art:

[0022] In this invention, the inner tube assembly can slide along the axial direction of the outer tube assembly, and the inner walls of the inner tube assembly and the outer tube assembly are locked together by a locking member. In the initial state, the inner tube assembly and the outer tube assembly are locked together, and the length of the telescopic sleeve is fixed. When the length needs to be adjusted, the locking member can be unlocked when the inner tube assembly is pushed down by the drill string, so that the inner tube assembly moves forward relative to the outer tube assembly, pushing the docking tool connected to the inner tube assembly toward the target, thereby achieving precise docking and being applicable to different drilling lengths. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the telescopic sleeve in an embodiment of the present invention;

[0025] Figure 2This is a schematic diagram of the lock-push assembly in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the inner tube assembly in an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram showing the connection between the intermediate tube, the sealing joint, and the sleeve joint in an embodiment of the present invention.

[0028] In the diagram: 1. Outer tube assembly, 1-1. Sealing joint, 1-2. Outer tube, 1-3. Sleeve joint, 2. Intermediate tube, 3. Inner tube assembly, 3-1. Inner tube, 3-2. Inner tube connector, 3-3. Guide block, 4. Locking push assembly, 4-1. Locking push joint, 4-2. Locking pusher, 4-3. Drill rod string, 5. Docking tool. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The purpose of this invention is to provide a telescopic casing and casing assembly to solve the problems existing in the prior art. It can achieve controllable extension to the bottom of the well, so as to actively adjust the distance between the docking tool and the target and adapt to different drilling lengths.

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Example 1

[0033] like Figures 1-4 As shown, this embodiment provides a telescopic sleeve, which is coaxially installed between the sleeve string and the docking tool 5. It mainly includes an outer tube assembly 1, an inner tube assembly 3, and a locking and pushing assembly 4. The top end of the outer tube assembly 1 is used to connect with the sleeve string; the inner tube assembly 3 is coaxially installed inside the outer tube assembly 1 and can move along the axial direction of the outer tube assembly 1. The bottom end of the inner tube assembly 3 extends out of the outer tube assembly 1 and is used to connect with the docking tool 5; the bottom end of the locking and pushing assembly 4 can be locked with the top end of the inner tube assembly 3 through a locking structure, and the top end of the locking and pushing assembly 4 is used to connect the drill string 4-3.

[0034] The inner tube assembly 3 and the bottom of the inner wall of the outer tube assembly 1 are locked together by a locking member. When the drill string 4-3 pushes the inner tube assembly 3 downward, the locking member can be unlocked, so that the inner tube assembly 3 can move forward relative to the outer tube assembly 1, realizing the controllable extension of the telescopic casing at the bottom of the well, thereby realizing the active adjustment of the distance between the docking tool 5 and the target.

[0035] Furthermore, it should be noted that in this embodiment, the top end refers to the end closest to the sleeve string, and the bottom end refers to the end closest to the docking tool 5.

[0036] In this embodiment, the inner tube assembly 3 can slide along the axial direction of the outer tube assembly 1, and the inner tube assembly 3 and the bottom of the inner wall of the outer tube assembly 1 are locked together by a locking member. In the initial state, the inner tube assembly 3 and the outer tube assembly 1 are locked together, and the length of the telescopic sleeve is fixed. When the length needs to be adjusted, the inner tube assembly 3 is pushed down by the drill string 4-3, which can unlock the locking member, so that the inner tube assembly 3 moves forward relative to the outer tube assembly 1, pushing the docking tool 5 connected to the inner tube assembly 3 toward the target body to achieve precise docking, which can be applied to different drilling lengths.

[0037] In this embodiment, as Figure 1 As shown, the outer tube assembly 1 mainly includes a sealing joint 1-1, an outer tube 1-2, and a sleeve joint 1-3. The sleeve joint 1-3 is connected to the top end of the outer tube 1-2 for connection with the sleeve. The sealing joint 1-1 is connected to the bottom end of the outer tube 1-2 and is locked to the inner tube assembly 3 by the locking member.

[0038] In this embodiment, the sealing joint 1-1 is a stepped cylindrical tube with a uniform inner diameter and a smaller outer diameter at the top. It extends into the outer tube 1-2 and is connected to the outer tube 1-2 by a set screw. Specifically, the portion of the sealing joint 1-1 extending into the outer tube 1-2 has multiple blind holes evenly spaced along the circumference at the middle position. The diameter of the blind holes is equal to (or slightly larger than) the outer diameter of the set screw. Correspondingly, the outer tube 1-2 has multiple through threaded holes evenly spaced along the circumference. The set screw is screwed through the threaded holes on the outer tube 1-2 and then inserted into the blind holes of the sealing joint 1-1, thereby connecting the sealing joint 1-1 to the outer tube 1-2. Furthermore, sealing grooves are machined on both sides of the blind holes (both sides along the axial direction of the outer tube 1-2) for installing O-ring seals (i.e., O-ring seals are provided on both sides of the set screw) to prevent pressure leakage during depressurization mining.

[0039] The casing connector 1-3 is also a stepped cylindrical tube with a larger outer diameter at the top and a casing nut machined inside for connection with the casing string. The bottom of the casing connector 1-3 has a smaller outer diameter, extending into the outer tube 1-2 and connected to it via a set screw. Specifically, the portion of the casing connector 1-3 extending into the outer tube 1-2 has multiple blind holes evenly spaced along its circumference at the middle position. The diameter of the blind holes is equal to (or slightly larger than) the outer diameter of the set screw. Correspondingly, the outer tube 1-2 has multiple through threaded holes evenly spaced along its circumference. The set screw is screwed through the threaded holes on the outer tube 1-2 and then inserted into the blind holes of the casing connector 1-3, thus connecting the casing connector 1-3 to the outer tube 1-2. Furthermore, sealing grooves are machined on both sides of the blind holes (along the axial direction of the outer tube 1-2) for installing O-ring seals (i.e., O-ring seals are installed on both sides of the set screw) to prevent pressure leakage during depressurization mining.

[0040] In this embodiment, the telescopic sleeve further includes an intermediate tube 2, which is a circular tube with a larger outer diameter at both ends and a smaller middle diameter, and a uniform inner diameter. It is coaxially disposed within the outer tube assembly 1, and one end of the intermediate tube 2 is connected to the sleeve joint 1-3 through a limiting structure, and the other end of the intermediate tube 2 is connected to the sealing joint 1-1 through a limiting structure. The limiting structure is used to restrict the relative rotation between the intermediate tube 2 and the outer tube assembly 1. The inner tube assembly 3 is slidably disposed within the intermediate tube 2 so that the inner tube assembly 3 can move along the axial direction of the outer tube assembly 1.

[0041] The limiting structure can be selected according to specific working needs; for example, a limiting key or a limiting groove structure can be selected. Specifically, such as... Figure 4 As shown, in this embodiment, multiple limiting keys are evenly distributed circumferentially at both ends of the intermediate tube 2. The limiting keys extend axially along the intermediate tube 2, while the sleeve joint 1-3 and the sealing joint 1-1 are correspondingly provided with multiple limiting grooves. The limiting keys are inserted into the corresponding limiting grooves to prevent the intermediate tube 2 from rotating within the outer tube assembly 1. In this embodiment, the limiting keys are preferably rectangular protrusions, and the limiting grooves are correspondingly rectangular grooves. The dimensions of both are machined to ensure that they can be inserted into each other with a small gap.

[0042] In this embodiment, the intermediate tube 2 is further provided with a guide groove along the axial direction, and the inner tube assembly 3 is provided with a guide block 3-3. The guide block 3-3 is slidably disposed in the guide groove, so as to realize the sliding of the inner tube assembly 3 in the intermediate tube 2 and restrict the relative rotation between the inner tube assembly 3 and the intermediate tube 2. Among them, multiple guide grooves are evenly provided along the circumference, preferably two, and neither end of the guide groove penetrates the end of the intermediate tube 2. Moreover, the width of the guide groove is slightly greater than or equal to the width of the guide block 3-3, so that the guide block 3-3 can slide in the guide groove.

[0043] In this embodiment, the limiting structure between the intermediate tube 2 and the outer tube assembly 1, as well as the guide groove and guide block 3-3 structure between the intermediate tube 2 and the inner tube assembly 3, can ensure that the telescopic sleeve extends and retracts in a fixed direction while transmitting torque, thereby achieving precise docking with the target.

[0044] In this embodiment, as Figure 3 As shown, the inner tube assembly 3 mainly includes an inner tube 3-1 and an inner tube connector 3-2. The bottom end of the inner tube 3-1 is machined with a male thread for threaded connection with the docking tool 5, and the inner tube 3-1 is locked to the sealing joint 1-1 via the locking element. The top end of the inner tube 3-1 is provided with a female thread for threaded connection with the male thread at the bottom end of the inner tube connector 3-2. The top end of the inner tube connector 3-2 can be locked to the locking push assembly 4 via the locking structure. In this embodiment, except for the male thread section at the end, the outer diameter of the inner tube 3-1 is equal front to back, and the outer surface is plated with hard chrome. Except for the female thread section at the end, its inner diameter is equal front to back.

[0045] Furthermore, in this embodiment, a sealing groove is formed between the male thread and the shoulder of the inner tube connector 3-2 for installing an O-ring to seal the gap between the inner tube connector 3-2 and the inner tube 3-1; two concave platforms are uniformly machined along the circumference of the middle part of the outer circle of the inner tube connector 3-2, the shape of the concave platforms is the same as that of the guide block 3-3, and two blind threaded holes are machined on the bottom plane of the platform for installing the guide block 3-3 onto the platform and fixing it with screws; and a sealing element is provided in the middle section of the inner hole of the inner tube connector 3-2 for sealing with the locking assembly 4, wherein the sealing element is vulcanized rubber provided on the inner wall or an O-ring installed by machining the sealing groove.

[0046] In this embodiment, the locking element is preferably a cylindrical locking pin. When the drill rod column 4-3 pushes the inner tube assembly 3 downward, the locking pin can be disengaged, thereby unlocking the device. The bottom end of the sealing joint 1-1 of the outer tube assembly 1 is tapered, with multiple pin holes evenly arranged circumferentially on the tapered surface. The pin holes penetrate the outer tube assembly 1 radially and are used to install the locking pin. The inner tube 3-1 has multiple blind holes corresponding to the end near its male thread. The diameter and number of the blind holes are the same as the pin holes on the sealing joint 1-1. The locking pin passes through the pin holes and extends into the corresponding blind holes, thereby locking the outer tube assembly 1 and the inner tube assembly 3.

[0047] In this embodiment, a sealing ring and a dustproof ring are also provided between the inner tube 3-1 and the sealing joint 1-1. Specifically, a dustproof ring installation groove and a sealing ring installation groove are provided on the inner wall of the sealing joint 1-1, and a dustproof ring and a sealing ring are installed respectively. On the one hand, this ensures that external mud does not enter between the inner tube 3-1 and the intermediate tube 2 during the expansion and contraction of the inner tube 3-1, thus ensuring a clean internal environment. On the other hand, it ensures that there is no pressure leakage when mud is injected into the drill string 4-3 for pressurization.

[0048] In this embodiment, as Figure 2 As shown, the locking push assembly 4 mainly includes a locking push rod and a locking push connector 4-1. The locking push connector 4-1 is located at the top of the locking push rod and is used to connect with the drill rod column 4-3. The bottom end of the locking push rod can extend into the inner tube connector 3-2 and be locked to it by a locking structure.

[0049] In this embodiment, the locking structure mainly includes a locking groove structure and a locking pusher 4-2. When the locking pusher 4-2 is screwed into the locking groove structure in a first direction (preferably clockwise), the inner tube assembly 3 and the locking push assembly 4 are locked. When the locking pusher 4-2 is rotated in a second direction (preferably counterclockwise), the locking groove structure can be unscrewed, thereby unlocking the inner tube assembly 3 and the locking push assembly 4. The locking groove structure is disposed on the inner tube connector 3-2, while the locking pusher is radially disposed on the locking pusher.

[0050] Specifically, the top of the inner tube connector 3-2 has an unequal inner diameter structure, and the circumference is evenly divided into four parts. The four parts are symmetrical in pairs. Two parts have larger diameters, which are greater than the length of the locking pusher 4-2, and two parts have smaller diameters, which are less than the length of the locking pusher 4-2. The inner tube connector 3-2 has two arc grooves uniformly machined in the opposite direction along the circumference at a certain distance from its top end face, forming the above-mentioned locking groove structure. From the end face along the axis, the two arc grooves are symmetrically opened. With the interface between the inner large-diameter arc and the small-diameter arc as the center, they extend equal arc distances L to both sides. This arc distance L is greater than the diameter of the locking pusher 4-2, so that the locking pusher assembly 4 can enter the inner tube connector 3-2 from the large-diameter section. After rotating clockwise by a certain angle, the locking pusher 4-2 enters the arc groove located in the large-diameter section. After rotating by a certain angle, it reaches the limit position of the arc groove located in the small-diameter section, ensuring that the drill rod string 4-3 does not reverse. Then the locking pusher assembly 4 and the inner tube assembly 3 are connected as one unit.

[0051] In this embodiment, the outer pipe assembly 1, intermediate pipe 2, inner pipe assembly 3, docking tool 5, and casing string are connected and lowered into place and hung at the wellhead. The drill string 4-3, connected to the locking push assembly 4, is then lowered into the well. After reaching the predetermined position, the locking push assembly 4 is inserted into the inner pipe connector 3-2 by rotating the drill string 4-3 clockwise. When the drill string 4-3 can no longer rotate, it indicates that the locking push assembly 4-2 has been inserted into the arc groove of the inner pipe connector 3-2, achieving locking between the inner pipe assembly 3 and the drill string 4-3. At this point, pressure is applied to the drill string 4-3. Push the inner tube assembly 3 forward. Since the casing string is already seated at the wellhead, when the drill string 4-3 is pressurized and pushed forward, the outer tube assembly 1 connected to the casing string remains stationary. Under the thrust, the locking pin between the inner tube assembly 3 and the sealing joint 1-1 is sheared (when the pressure of the drill string 4-3 first rises and then falls, it proves that the locking pin between the inner tube 3-1 and the sealing joint 1-1 has been sheared), thus allowing the inner tube assembly 3 to extend forward. Once the docking tool 5 connected to the inner tube assembly 3 has docked with the target, the forward extension can be stopped at any time. At this point, the drill string 4-3 can be rotated in the opposite direction. After rotating a certain angle, the locking pusher 4-2 reaches the reverse limit position of the arc groove and can no longer be rotated. Then, lift the drill string 4-3 upward, and pull the locking pusher assembly 4 and the drill string 4-3 out of the well together.

[0052] The present invention also provides a casing assembly, including the docking tool 5, the casing string and the telescopic casing as described above, wherein the total length of the casing string and the docking tool 5 is less than the drilling length.

[0053] In this invention, a telescopic sleeve is added between the casing string and the docking tool 5. After the upper casing string is mounted, the drill string 4-3 is lowered in, and the drill string 4-3 pushes the inner tube assembly 3 to extend, so as to achieve precise docking between the docking tool 5 and the target. Moreover, in this embodiment, the telescopic sleeve is designed with a multi-stage sealing form, which can ensure that no leakage occurs when the drilling fluid flows through the telescopic sleeve and during pressurization.

[0054] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A telescopic sleeve, characterized in that: The device includes an outer tube assembly, an inner tube assembly, and a locking and pushing assembly. The top end of the outer tube assembly is used to connect with a casing string. The inner tube assembly is coaxially mounted inside the outer tube assembly and can move along the axial direction of the outer tube assembly. The bottom end of the inner tube assembly extends out of the outer tube assembly and is used to connect with a docking tool. The bottom end of the locking and pushing assembly can be locked to the top end of the inner tube assembly through a locking structure. The top end of the locking and pushing assembly is used to connect to the drill string. The inner tube assembly and the inner wall of the outer tube assembly are locked together by a locking member. When the drill string pushes the inner tube assembly downward, the locking member can be unlocked, so that the inner tube assembly can move forward relative to the outer tube assembly. The outer tube assembly includes a sealing joint, an outer tube, and a sleeve joint. The sleeve joint is connected to the top end of the outer tube for connection with the sleeve in series. The sealing joint is connected to the bottom end of the outer tube and is locked to the inner tube assembly by the locking member. The telescopic sleeve also includes an intermediate tube, which is coaxially disposed within the outer tube assembly. One end of the intermediate tube is connected to the sleeve joint via a limiting structure, and the other end of the intermediate tube is connected to the sealing joint via a limiting structure. The limiting structure is used to restrict the relative rotation between the intermediate tube and the outer tube assembly. The inner tube assembly is slidably disposed within the intermediate tube so that the inner tube assembly can move axially along the outer tube assembly. The intermediate tube is provided with a guide groove along the axial direction, and the inner tube assembly is provided with a guide block, which is slidably disposed in the guide groove; The locking structure includes a locking groove structure and a locking pusher. When the locking pusher is screwed into the locking groove structure in a first direction, the inner tube assembly and the locking pusher assembly are locked. When the locking pusher is rotated in a second direction, it can be screwed out of the locking groove structure, thereby unlocking the inner tube assembly and the locking pusher assembly. The locking groove structure is provided on the inner tube assembly, including two arc grooves arranged in opposite directions along the circumference. The locking pusher is provided on the locking pusher assembly and extends radially along the locking pusher assembly. A sealing element is also provided on the inner wall of the inner tube assembly near the locking pusher assembly to achieve a seal with the locking pusher assembly.

2. The telescopic sleeve according to claim 1, characterized in that: Both the sealing joint and the sleeve joint are installed on the outer tube by set screws, and sealing rings are provided on both sides of the set screws.

3. The telescopic sleeve according to claim 1, characterized in that: The inner tube assembly includes an inner tube and an inner tube connector. The bottom end of the inner tube is provided with a male buckle for connecting with the docking tool, and the inner tube is locked to the sealing joint by the locking member. The top end of the inner tube is provided with a female buckle for connecting with the inner tube connector, and the top end of the inner tube connector can be locked to the locking push assembly by the locking structure.

4. The telescopic sleeve according to any one of claims 1-3, characterized in that: The locking element is a locking pin. When the drill string pushes the inner tube assembly downward, the locking pin can be disengaged to unlock the assembly. The outer tube assembly has multiple pin holes evenly arranged circumferentially at its front end, and the pin holes penetrate the outer tube assembly radially. The inner tube assembly has multiple blind holes correspondingly arranged on it. The locking pin passes through the pin holes and extends into the corresponding blind holes to lock the outer tube assembly and the inner tube assembly.

5. The telescopic sleeve according to claim 1, characterized in that: A sealing ring and a dustproof ring are also provided between the inner tube assembly and the front inner wall of the outer tube assembly.

6. A sleeve assembly, characterized in that: It includes the docking tool, the sleeve string, and the telescopic sleeve as described in any one of claims 1-5.

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